Watercress oil (WCO) is the seed oil of Nasturtium officinale, Brassicaceae family. WCO is a cosmetic for hair growth approved by the Saudi Food and Drug Authority (SFDA). The study aimed to analyze by GC–MS, the phytochemical profile and the safety of WCO as a cosmetic according to SFDA, validates the traditional method of applying hot oil mixtures to the scalp, and also reports the pH, UV absorption, and in-silico binding mechanism of fatty acids for hair growth. The absorption of UV-B light (284.50 nm and 290.60 nm) by WCO suggests that it acts as a sunscreen for the scalp. The pH of the marketed WCO, 5.53 ± 0.02, shall not damage the scalp and hair. The GC–MS analysis confirmed fatty acids as the principal constituents (65.65%) of WCO composed of monounsaturated fatty acids (MUFAs): cis-11-Octadecenoic acid (17.14%), cis-9-Octadecenoic acid (17.11%), cis-13-Eicosenoic acid (11.13%), cis-11-Eicosenoic acid (3.48%), and cis-13-Docosenoic acid (1.64%); saturated fatty acid: n-Hexadecanoic acid (12.89%); saturated fatty alcohol: Docosanol (2.26%). The GC–MS results also confirmed the absence of colorants, toxic solvents, and therapeutic substances in WCO, a cosmetic requirement, according to SFDA. The densities of mixtures of WCO + Coconut oil was 0.801 ± 0.03 mg/mL, and WCO + Olive oil was 0.885 ± 0.01 mg/mL; the kinematic viscosities of WCO + Coconut oil was 21.5 ± 0.0 mm²/s, and WCO + Olive oil was 28.6 ± 0.1 mm²/s at 40℃, which was lesser than the mixtures at 27℃. The decrease in density and viscosity of hot oil mixtures can improve the penetration of oil into the hair filament, which substantiated the traditional application method. In-silico, molecular docking results revealed that all the fatty acid constituents except Docosanol contributed to the hair growth promotion effect by activating MAPK1, MAPK3, and MAPKp38 receptors. This work is the first report on WCO to establish the phytochemical profile to confirm SFDA standard by GC–MS and its in-silico efficiency of activation of MAPK receptors for hair growth.

西洋菜油（WCO）是十字花科植物金莲花的种子油。WCO是经沙特食品和药物管理局（SFDA）批准用于头发生长的化妆品。目的是通过GC-MS，植物化学物质分布和根据SFDA作为化妆品WCO的安全性，分析研究证实施加热油的混合物到头皮的传统方法，并且还报道了pH值，UV吸收，和IN-硅片脂肪酸对头发生长的结合机制。WCO对UV-B光（284.50 nm和290.60 nm）的吸收表明，它可作为头皮的防晒霜。市售WCO的pH值为5.53±0.02，不得损坏头皮和头发。GC-MS分析确认，脂肪酸是WCO的主要成分（65.65％），由单不饱和脂肪酸（MUFA）组成：顺式-11-十八碳烯酸（17.14％），顺式-9十八碳烯酸（17.11％），顺式-13-二十碳烯酸（11.13％），顺式-11-二十碳烯酸（3.48％）和顺式-13-二十二碳六烯酸（1.64％）; 饱和脂肪酸：正十六烷酸（12.89％）；饱和脂肪醇：二十二烷醇（2.26％）。根据SFDA的报告，GC-MS结果还证实WCO中没有着色剂，有毒溶剂和治疗性物质，这是化妆品的要求。WCO +椰子油的混合物的密度为0.801±0.03mg / mL，WCO +橄榄油为0.885±0.01mg / mL。WCO +椰子油在40℃时的运动粘度为21.5±0.0 mm ² / s，WCO +橄榄油在40℃时的运动粘度为28.6±0.1 mm ² / s，低于27℃时的混合物。降低热油混合物的密度和粘度可以提高油在发丝中的渗透，从而证实了传统的涂抹方法。硅内分子对接结果显示，除二十二烷醇外，所有脂肪酸成分均通过激活MAPK1，MAPK3和MAPKp38受体来促进头发生长。这项工作是关于WCO的第一份报告，该报告建立了植物化学特征以通过GC-MS确认SFDA标准以及其在毛发生长过程中激活MAPK受体的计算机活性。